


A Spiral into Obsession

by BubblyShip



Category: Undertale (Video Game)
Genre: Ambiguous/Open Ending, Crazy, Everyone Needs A Hug, F/F, F/M, Female Frisk (Undertale), Frisk is messed up, Growing Up, Insanity, Obsession, One-Sided Attraction, Sad Toriel, Sans (Undertale) Needs a Hug, Stalking, Teenage Frisk (Undertale), Unrequited Crush, Unrequited Love, Yandere, Yandere Frisk, everyone is scared for Frisk, insane frisk, like at all, sans is not into it, scared sans
Language: English
Status: Completed
Published: 2020-01-14
Updated: 2020-01-14
Packaged: 2021-02-27 14:26:33
Rating: Not Rated
Warnings: Underage
Chapters: 1
Words: 2,069
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22258669
Author URL: https://archiveofourown.org/users/BubblyShip/pseuds/BubblyShip
Summary: Everyone had been so excited when the pacifist human fell underground. Frisk was the perfect human, she got along with everyone and spared all of their lives, she even freed all monsters to the surface.But there was just one small problem with her that made everyone concerned.She keeps just… staring at Sans.It’s starting to get creepy.
Relationships: Alphys/Undyne (Undertale), Frisk/Sans (Undertale)
Comments: 8
Kudos: 92





	A Spiral into Obsession

It started with just a simple handshake. 

This entire mess started with a dumb handshake.

Sans remembered the first day he met Frisk. They were small for a kiddo, large yellow eyes and an innocent look. Like a child should be. 

No one, not even himself, noticed it at first. Frisk was just a kid, Sans had simply thought they did that with everyone. Frisk would follow him around from time to time, and sometimes get jealous if Sans didn’t give the kid any attention. With a laugh and a pat on their head, Sans had dismissed them everytime. Soon, the surface was opened to the Monsters, and Sans had thanked the kid with a hug.

They didn’t let go of him, everyone noticed how long Frisk held on.

Once again, they had all assumed it was just the child side of Frisk that had attached onto Sans as an Uncle figure or something. Toriel was a bit sad that Frisk didn’t give her the same treatment, but you couldn’t force a child to love you, you had to earn it.

Everyone was just confused to how only Sans had seemed to earn that special child love.

He just made jokes about it at first, saying things about how he was just a natural Dad and that he was going to be like a Mother duck with her young following behind him, just as Frisk did. Frisk was just a cute kid that would follow Sans around from time to time, sometimes get a little pout face if he didn’t return the attention. 

It wasn’t so cute when Frisk grew up.

Somehow, Sans wasn’t the one who saw it first. It was Toriel that found the notebook, approaching Sans while Frisk was doing her homework.

Sans could remember the time, he was making pasta puns while Papyrus cooked spaghetti. Intending to include her on the puns, Sans had turned towards her, expecting her to join in, but her face clearly displayed something was wrong. Papyrus saw it too.

The notebook was filled with drawings of Sans. Some were of just his head, others were of him in random, revealing outfits, but all of them were surrounded by hearts. Frisk was in high school at that time, they were too old to be considered cute now with this. 

“What should we do?” Toriel had asked at the time.

Sans didn’t want to get involved in too much drama, so he wanted to keep it more simple. “We can just try to ignore it. Frisk might grow out of it, you know? Maybe I’ll just make myself a little more farther from her, you can hint at some guys in her class, like Monster Kid?”

“We can try that first.” Toriel had the same interest of not creating more problems with Frisk. “It could just be a little crush. She did admire you as a child, her hormones are just acting up on you, that’s probably the cause.”

“Exactly, we just gotta wait for it to be over,” Sans said.

That’s when pie night and friend dinners stopped for Sans. He didn’t want to encourage this disturbing crush, so they both had agreed to cut off contact with Frisk for awhile, and explained to the others why they were doing that. Just let Frisk cool off and figure herself out, that was all.

Frisk didn’t take it well. 

Toriel had kept the others updated on Frisk. The first day had went by smoothly, Frisk didn’t know about the rule. The second day was a friend dinner, so Sans decided to make himself scarce by going to a poker game with his Snowdin buddies. 

Apparently, Frisk had insisted to know why Sans was missing so much that Toriel had to spill the beans about what she had found. Then, for the rest of the meal, she had stared silently at her food without touching it. No words, no yelling. 

Everyone was worried for Frisk. Frisk was the human who took action and defeated both Asgore and Omega Flowey, they did things when they believed something was wrong and could be done. Toriel decided to take Frisk to therapy, just in case.

Then, suddenly, everything just seemed to… fix itself.

Frisk’s grades went up, she even got a 4.0 on her GPA. She started doing better in Student Council, and she even was elected to be the President. Toriel had looked in her notebook again, and all of the pages with Sans were torn out. Frisk seemed to be acting more normal, she called Toriel Mom for the first time. The therapist had said Frisk was doing great.

Sans had made sure to stay away from Frisk for a bit longer, but when she had announced she was dating someone named Mark from school, Toriel and Sans agreed that he could attend the next pie night at her house.

It started off normal, the most normal it had ever been. Frisk didn’t stare at him the entire time. Frisk didn’t purposefully sit next to him or follow him. Frisk called Toriel Mom.

They all had a good time, and it was good.

With that going well, they decided that Sans could start attending events with everyone else again. Frisk, for the first time in their life, treated Sans normally, and it was nice. Sans didn’t look up to find Frisk staring at him intently, or turn around to find her following him. It was like he was a normal person, that Frisk didn’t have an obsession with him anymore.

Until holes in her story started to show.

Toriel had learned a month later that there was no one in Frisk’s class named Mark. She had asked Frisk about it one day, and Frisk had told Toriel that she lied so Toriel wouldn’t worry about her. The therapist had then called, a week later, telling Toriel about the latest session. Frisk had showed some disturbing dark sides to her personality that had him reconsidering if she was fully sane.

The final straw was when Undyne had found the pictures.

She had decided to clean up Frisk’s room while she was at school, and she had found the loose floorboard on the floor and sent pictures of what she found to everyone while calling Toriel to tell her something was wrong.

Sans had to sit down after what he saw, making sure his room door was locked.

Seven pairs of his underwear, the ones he thought he lost over several years. The torn pages from the notebook was in there. Some used forks and spoons, probably used by Sans last, were placed in bags with no air in them, like they were somehow valuable and couldn’t be tainted. But the most disturbing items from the collection was the printed photographs.

They dated back to when Sans was still underground, judging by how he looked younger in some of them. Some of them were taken from the distance, from behind bushes and trees, others were through windows. And some…

He was sleeping in most of them, and you could see Frisk’s hands in some of the pictures. Some were just of him sleeping, others were Fisk holding up his shirt or pulling back his pants to take pictures of his bones, some were close ups of his sleeping face or bare bones.

The creepiest picture was the one they had took after they arrived on the surface. They had all posed for a picture that day, Sans had been next to Frisk in it. Everyone else’s faces were scribbled out with a crayon, and his and Frisk’s faces were circled together by a heart.

This was concerning.

“I dunno, Paps, what should we do? I-I mean, Frisk literally has nudes of me and… oh my Toby Fox, I dunno,” Sans said, “Should we talk to Frisk about it? Should we put her in some sort of helping place or something?”

“I’M NOT SURE SANS!” Papyrus watched Sans pace back and worth. “BUT SHE HAS AN UNHEALTHY OBSESSION WITH YOU, IT LOOKS LIKE SHE JUST STARTED KEEPING IT MORE SECRET TO GET TO SEE YOU AGAIN.”

“Yeah, but we can’t just limit Frisk from me more. I mean, the kid has nudes of me while I was sleeping! That’s just so creepy!” Sans said, “I’m going to have to lock my door, I might even go stay at a hotel for a bit.”

“FRISK ONLY HAD A COUPLE OF SLEEPOVERS WITH US BEFORE, THERE WERE TOO MANY PICTURES TO BE JUST FROM THE SLEEPOVERS, THEY MUST HAVE SNUCK INTO OUR HOUSE FROM HER HOUSE.”

“I should get locks for my windows, just in case,” Sans said, “But we have to put Frisk into a place or something. We can’t just ignore it.”

Over the phone, Toriel had agreed with Sans about his conclusion, as did everyone else. After this many years of the following and obsession, and with all of those stolen items, Frisk had to be dealt with. They couldn’t just limit Sans from her, this was way too far now.

They had all turned to the therapist, asking him for what best actions would help Frisk overcome her unhealthy desire for Sans. They told him everything about what they had found, and he suggested some courses of action to give her the help she needed.

Sans had stayed at his house under lock and key with Papyrus while everyone else had told Frisk the situation when she arrived home. Her therapist knew of a mental hospital where she would be taken away from Sans and helped, removing him completely from her life and watching her to make sure she wouldn’t be able to go to his house. Sans wouldn’t be allowed to visit her, and Frisk wouldn’t be allowed to see Sans.

Everything about Frisk had changed. They weren’t such an innocent kid anymore, they knew this was wrong, they had to. Sans didn’t want to do this, neither did Papyrus, but the pictures were enough evidence to get a restraining order if he wanted to.

Frisk hadn’t taken the news well. Toriel had received a full blown punch to the face that knocked her down, Undyne had told the skeleton brothers how she was forced to knock the kid out before she could kill Toriel. 

Papyrus broke into tears.

Sans was scared for their safety.

Now being deemed a danger to others, Frisk was immediately placed in the mental hospital for both her and others safety. After the first night, Toriel had tried to visit Frisk, but she was only attacked again.

He knew because Toriel had come back with a blackened eye and stained eyes from crying. But there was nothing Sans could do, if he tried to talk to Frisk, it could just make the obsession worse. It was already bad enough, Frisk attacked everyone that went close to her, she screamed Sans’s name constantly, her therapist said she should have been limited from Sans years ago. The obsession was too far along, even hearing about Sans could make her snap at this point.

Everyone blamed themselves. Sans said he should have never supported her following him, he should have never let this grow to the point where it was now. Toriel said she wasn’t a good Mother. Asgore said he failed at leading Frisk down a right path. Undyne said she failed at being Frisk’s friend. Alphys blamed herself for not being there when Frisk needed someone the most. Papyrus claimed it was his fault due to his ignorance to the situation, that he should have protected Sans when Sans needed it.

Just maybe, the blame was no one’s. None of them had done wrong, they did the best they could in the situation.

But looking down at the phone, Sans felt as if he had somehow failed the kid. Just a couple of months ago, she was the nice but quirky human that freed monsters and was the kid he thought of like her own niece, in a sense. But now Frisk was someone he didn’t even know, a mere child with such an intense crush that she is willing to attack her own Mother and sneak into his bedroom to take pictures of him naked.

With a sigh, Sans brought the phone up to his head once more. 

“Yeah, I want to make a restraining order on Frisk.”

**Author's Note:**

> Make sure to check out more stories like this on my Wattpad, BubblyShip!


End file.
